Turning Archive 2007

Subject:

Which Talon jaws for small turnings?

Joe Pack>I need a set of small jaws for my Talon chuck for turning small objects. My immediate need is for a set of jaws I can use to hold pocket watch blanks, but will use them for turning votive candle cups also. I rough cut pocket watch blanks to 2"x3/4", then drill a 1 3/8" diameter x 5/16" deep hole with a Forstner bit. (I rough cut candle cups to 2 1/2""x2" and drill 1 5/8" holes.) I have been mounting this on a Penn State adjustable collet chuck, but, on my 6th blank, the chuck "blew apart" on me...metal chunks flying (I found 2 pieces, looking for others around the shop and in the shavings pile). I had almost no pressure on the tool when it flew, and the chuck was TIGHT when I started. It had a tendency to loosen in use, but... Anyhow, it blew, I can't find the pieces, wouldn't trust it again if I did, and I don't want to mess with a toy again.

I found two sets of jaws that would fit the bill. One is the #1 spigot jaw set. The other is a step jaw set. The #1 set has an internal max/min of 2 3/8" - 1" and an external max/min of 1 5/8 - 1/4". The step jaw set has a max/min of 2 3/8" - 7/8" and an external max/min of 1 3/4" - 3/8". Either would fit the bill for my pocket watch job. What I don't know is the functionality of the step jaws versus the straight jaws. The spigot jaws would seem to have a much deeper "reach" if needed, but can be used in a shallow hole. The step jaws would fit in a shallow hole using the smallest diameter step, but would seem to be difficult to use the larger/largest step if the hole was shallow.

I have the #2 and #3 jaws already.

What would you recommend for my intended smaller projects? Step jaw or straight jaw? Also, would you recommend smooth or grooved for these smaller items? Indentations on the pocket watches won't show, but they might on some other work. Would I be making a mistake with smooth jaws?